microchronometer

Definitions

from Wiktionary, Creative Commons Attribution/Share-Alike License

n. A chronoscope.

from the GNU version of the Collaborative International Dictionary of English

n. A chronoscope.

from The Century Dictionary and Cyclopedia

n. An instrument for registering very small periods of time, such as the time occupied by the passage of a projectile over a short distance: a kind of chronograph. Also called, corruptly, micronometer.